<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        input {
            border: 0;
        }
        div {
            width: 200px;
            height: 200px;
            border-width: 1px;
            /* 实线 */
            /* border-style: solid; */
            /* 虚线 */
            /* border-style: dashed; */
            /*点线*/
            /* border-style: dotted; */
            /* 双线 */
            /* border-style: double; */
            border-color: red;
        }
        .it{
            border-color: blue;
            border-width: 1px;
            border-style: dotted;
        }
        
        .nc{
            border-top: 1px solid green;
        }
        .email{
            border-bottom: 1px solid red;
        }

        .tel{
            border: 1px solid gray;
            margin-left: 5px;
        }
    </style>
</head>
<body>
    <div>
        我是一个盒子
    </div>

    <br>

    用户名<input type="text" class="it">
    昵称<input type="text" class="nc">
    邮箱<input type="text" class="email">
    手机<input type="text" class="tel">
</body>
</html>